I needed a bending wrench in a hurry one day and came up with this........( the wrench in the center).....First I drew out the handle then I simply drilled two holes in the un forged end of the 3/4 x 1'' flat bar to accept two pieces of 5/8'' round sucker rod (medium carbon). The holes were close to a press fit so the rounds were firmly captured before welding on the opposite side of the forks. Small welds were put on the business side as well, away from the bending area. They've proved to be very durable. Just like any other bending fork, if you're too heavy handed with em they will spread...... There are no corners to file so they don't leave hash marks in the steel...................mb

I needed a bending wrench in a hurry one day and came up with this........( the wrench in the center).....First I drew out the handle then I simply drilled two holes in the un forged end of the 3/4 x 1'' flat bar to accept two pieces of 5/8'' round sucker rod (medium carbon). The holes were close to a press fit so the rounds were firmly captured before welding on the opposite side of the forks. Small welds were put on the business side as well, away from the bending area. They've proved to be very durable. Just like any other bending fork, if you're too heavy handed with em they will spread...... There are no corners to file so they don't leave hash marks in the steel...................mb

looking good

Ive got a couple like that but they did not held up well just being mild steel.. . Maybe I should give some better steel a try... I would think the weld is iffy with the sucker rod? I have tried welding sucker rod right to things and it snapping due to carbon localization.... If they are super tight in the hole it might be that the weld really isnt doing much other than keeping it from creeping?

I have a few like this, as well as forged ones. One of the things I like about the fabricated ones is that they have less of a tendency to put a twist in the bend because all of the working surfaces are parallel. I frequently use bending forks butted up against each other or overlapping and if the legs are tapered on backside it introduces even more twist than I do on my own.

I think the tight fit absorbs a lot of the bending stresses rather than the weld. I sometimes do a fake post-heat on things like this by putting taking an extra welding pass on the mild steel side of the weld in the hopes that the extra heat will slow the cooling of the tool steel and prevent any hardening at the weld margin.

I would say the two main factors for a good tool is a beefy head for the pins and good steel for the pins. The weld on the work side is likely not necessary and may even cause stuff like sukker rod to snap as Larry said (huge metallurgical variations in that stuff). A weld for each pin on the backside shouldn't wreck the heat treatment of the pin...........
I made a set to fit into the trailer hitch receiver of my truck for field bending as well........

Would coil spring work for this or will it flex or break? I would like to make some bending wrenches but if spring will not work I will get something better. Thanks - Jerry P.

Ive got a couple like that but they did not held up well just being mild steel.. . Maybe I should give some better steel a try... I would think the weld is iffy with the sucker rod? I have tried welding sucker rod right to things and it snapping due to carbon localization.... If they are super tight in the hole it might be that the weld really isnt doing much other than keeping it from creeping?

Decent preheat of the parts (good black heat or even just barely dull red, then weld with 7018 or equivalent for higher carbon steels. If extra critical, post heat as well.

When I make pins for such devices I generaly use grade 8 bolts, since I stock them I have a good range of length/diameter available. On the subject, I often use grade 8 bolts for tool steel also, for example flypress or hossfeld tooling.

That's exactly how I was going to build my bend forks whenever I get around to it. A 1/2" reamer should just about give a press fit on steel dowels of the same size which any machine shop has a few laying around. A small tack weld on the back side even if hard cracking occurred should hold the dowels in place for the purpose. Did you make a couple extra ones for me?